1. Field of the Invention
The invention relates to an image forming apparatus and to its control method.
2. Related Background Art
In association with the digitalization of copying apparatuses, a hybrid apparatus having a plurality of functions, such as a facsimile function for performing facsimile transmission and reception by using a scanner function, a printer function, a PDL (Page Description Language) printer function, and the like, has been put into practical use. Such a hybrid apparatus can operate not only as a single function, such as a copy function, facsimile function, PDL printer function, or the like, but also, among a plurality of functions, such that a PDL developed image is facsimile transmitted, and the like. Further, by connecting the hybrid apparatus via a LAN, the functions of the hybrid apparatus can be used by computer apparatuses, and the like.
In a copying apparatus, an apparatus having a function for performing a charging process in accordance with a paper size of a copied image, a kind of paper, the number of papers, color/monochrome, or the like, has been put into practical use. In such a copying apparatus, the user can set a copy irrespective whether sufficient coins have been inserted or not, and a control, such that the copying operation is not started or is interrupted, if the coins are insufficient at a stage when the copy is actually executed in accordance with the setting, is performed.
If a charging system of the coin throw-in type, in the same format, is applied to a PDL printer or a hybrid apparatus having a PDL printer function, there are the following problems.
If print data can be sent from a computer before the coins are thrown in, another user cannot use such an apparatus until coins are thrown in.
Even if there is no user who wants to use the apparatus, the received data has to be stored until coins are thrown in. This results in an increase in the capacity of a memory and causes an increase in costs. A timing control of erasure of data, and the like, also has to be performed, and the control becomes complicated.
In the case of a copy, unless a necessary amount of money is paid, an original is not read. In the case of the PDL printer function, however, a necessary amount of money is unknown until sufficient data is received and analyzed. Therefore, when data of a plurality of pages is received at one time, there is a possibility that the amount of money paid by the user is insufficient, before all of the data which has already been received, is printed. However, such a situation is not presumed in the charging system of the coin throw-in type used in a conventional copying apparatus.
During the printing of the data of a plurality of pages, if the printing cannot be performed at the halfway point due to convenience of an amount of money, or the like, possessed by the user, and there is data remaining in the hybrid apparatus without being printed, there is a concern that when another user intends to make a copy by using the copy function and throws coins into the apparatus, the remaining data is outputted as unusable data.
In a state when a user forgets to remove an original, and there is a copy original on a copyboard, if another user intends to print a copy by using the printer function, throws coins into the apparatus, and presses a start key, there is also a concern that a copy of the original on the copyboard is outputted as being unusable data.
In the conventional copying apparatus, since the originals are read one by one (every single side) in a both-side copying mode, each time a single side is printed, a process is interrupted, and the copy is executed while charging. The reason why there is not trouble, even if the printing to a single side is interrupted mainly at the time of a platen, as mentioned above, is because the user himself who requested the both-side printing performs the printing by inserting coins while perceiving the progress of the operation.
In the case of the PDL data, in the both-side printing mode, since the printing of the data for both sides is requested in a group, the charging process of the conventional copying apparatus, which performs the charging process for every single side, cannot be used as it is, in common.
That is, if only the data for a single side is printed due to an insufficient fee (coins), or the like, in spite of a fact that the data for both sides has been received, a complicated process is requested of the user. For example, when the user sends data for two pages, if only a single side is printed, in order to print the second side, the user has to edit the data and send the data of only the second side again.
As mentioned above, if the conventional copy charging system of the coin throw-in type is applied to the PDL printer or the hybrid apparatus having the PDL printer function, various problems arise.